Power extractor detecting power and voltage changes

ABSTRACT

In some embodiments, a power extractor utilizes power transfer circuitry with analysis circuitry to detect a power slope and to control the magnitude of the current in response to the detected power slope. The power analysis circuitry may increase the current as long as the power slope shows an increase in power and may decrease the current as long as the power slope shows a decrease in power. The magnitude of the current is responsive to the duty cycle of the switching circuitry and to the detected power slope. Other embodiments are described and claimed.

This U.S. application claims priority to Provisional Application No.60/867,342 entitled XSLENT Power Extractor (XPX) filed on Nov. 27, 2006and to Provisional Application No. 60/888,486 entitled Power ExtractorConverter (XPX Converter) filed on Feb. 6, 2007.

RELATED APPLICATIONS

This Application is related to the following U.S. patent applicationSer. No. 11/774,562, entitled “Power Extractor Detecting a PowerChange”, filed Jul. 7, 2007; Ser. No. 11/774,563, entitled “PowerExtractor with Control Loop”, filed Jul. 7, 2007; Ser. No. 11/774,564,entitled “System and Apparatuses with Multiple Power Extractors Coupledto Different Power Sources”, filed on Jul. 7, 2007; Ser. No. 11/774,565,entitled “Power Extractor for Impedance Matching”, filed on Jul. 7,2007.

FIELD

Embodiments of the invention relate generally to electrical power andmore particularly to apparatuses, methods and systems including a powerextractor for DC-to-DC power transfer between a source and a load.

BACKGROUND

The commercial switched-mode power supply industry was beginning to growduring the 1970s, and the theory and technology of switched-modeconversion was being understood as part of the academic discipline ofPower Electronics. The Power Electronics Group of the CaliforniaInstitute of Technology (Caltech) in California, USA developed themodels for the three basic DC-to-DC switching regulator topologiesalready developed, namely the buck, boost and buck-boost converters.From this work stemmed the modeling and analysis method calledstate-space averaging which allowed the theoretical prediction of aconverters frequency response, and therefore a better understanding of aswitched-mode regulator's feedback loop and stability criteria. Furtherwork at Caltech, especially by Slobodan Ćuk (1976) produced a fourthmember of the basic DC-to-DC switching regulators which has beendescribed as an optimum topology because of its symmetrical structureand non-pulsating input and output currents. This topology DC-to-DCswitching regulator is now commonly known as the Ćuk converter.

The theorem known as the maximum power theorem (Jacobi's Law) states:“Maximum power is transferred when the internal resistance of the sourceequals the resistance of the load, when the external resistance can bevaried, and the internal resistance is constant.”

Solar power is a clean and renewable source of energy. Solar power, orsolar energy, is the technology of obtaining usable energy from thelight of the sun. A photovoltaic cell is a device for converting lightenergy into electricity. Photovoltaic cells are often used specificallyto receive sunlight (and are called solar cells), but may respond tolight from other sources. A solar cell array or module or panel is agroup of solar cells electrically connected and packaged together. Whilethe interest in solar power is high, the high cost of producing solarcells and arrays coupled with the traditionally low energy efficiency ofthese devices prevents widespread usage of solar power. Given thevariations in sunlight (clouds, rain, sunrise, sunset, altitude,latitude, etc.), solar power is an example of an unstable energy source.Unstable power sources may include natural power sources, but may alsoinclude man-made power sources. As with solar energy, minimizing powerloss is a significant challenge when attempting to extract and/orconvert energy from unstable power sources to stable, useable forms ofpower. Other examples of power sources include, but are not limited to,wind, water, heat, tidal forces, heat (e.g., thermal couple), hydrogenpower generation, gas power generation, radioactive, mechanicaldeformation, piezo-electric, and motion (e.g., human motion such aswalking, running, etc.). Other power sources may be stable (providing anessentially constant power but variable in magnitude).

Prior techniques have been employed to improve the efficiency of solarcells. One of the earliest improvements was the addition of a battery toa solar cell circuit to load level the electrical output from thecircuit during times of increased or decreased solar intensity. Initself, a photovoltaic or solar array can supply electrical powerdirectly to an electrical load. However, a major drawback of such aconfiguration is the diurnal variance of the solar intensity. Forinstance, during daylight operation, a solar cell produces excess powerwhile during nighttime or periods of reduced sunlight there is little orno power supplied from the solar cell. In the simplest electrical loadleveling scenario, the battery is charged by the solar cell duringperiods of high solar radiation, e.g., daylight, and the energy storedin the battery is then used to supply electrical power during nighttimeperiods.

A single solar cell normally produces a voltage and current much lessthan the typical requirement of an electrical load. For instance, atypical conventional solar cell provides between 0.2 and 1.4 Volts ofelectrical potential and 0.1 to 5.0 Amperes of current, depending on thetype of solar cell and the ambient conditions under which it isoperating, e.g., direct sunlight cloudy/rainy conditions, etc. Anelectrical load typically requires anywhere between 5-48 Volts (V) and0.1-20 Amperes (A). The industry's standard method of overcoming thismismatch of electrical source to load is to arrange a number of solarcells in series to provide the needed voltage requirement and arrange inparallel to provide the needed current requirement. These arrangementsare susceptible if the output of individual cells within the solar cellarray is not identical. These differences have a negative effect on thearray's ability to efficiently convert solar energy into electricalenergy. The array's output voltage or current will drop and the arraymay not function to specification. For example, a common practice it isto configure a solar cell array for an output voltage of 17 V to providethe necessary 12 V to a battery. The additional 5 V provides a safetymargin for the variation in solar cell manufacturing and/or solar celloperation (e.g., reduced sunlight conditions, temperature variationswithin the array, or just dirty cells within the array).

Continuing with this scenario, assuming that the current produced bytraditional solar cell arrays is constant, the solar cell array losesefficiency due to the panel array being 5 volts higher than the batteryvoltage. For example, a solar cell array rated for 75 Watts (W) at 17Volts will have maximum current of 75 divided by 17, which equals 4.41Amperes. During direct sunlight, the solar cell array may actuallyproduce 17V and 4.41 A. However, given that the battery is rated at 12V,in this scenario, the power transferred will only be 12V at 4.41 A,which equals 52.94 W and results in a power loss of about 30%. Thismargin creates a significant power loss; and is typical of what is seenin actual installations where the cell array is connected directly tothe batteries, however, it is not desirable to reduce the margin voltageprovided by the solar cell array because under reduced sunlightconditions, the voltage potential produced by the solar cell array willdrop due to low electron generation, and thus might not be able tocharge the battery or will consume power from the battery that it wasintended to charge.

FIG. 1 illustrates a prior art system for generating solar power.Photovoltaic (PV) cells 12, 14, and 16 are connected in series to a load26 through protective circuitry 22 (such as a diode). In the examplediscussed above, a protection circuit that would prevent the reverseflow of power into the array (e.g., protective circuitry 22) couldconvert a 17V, 4.41 A input from a solar cell array (e.g., PV cells12-16) to a 12V and 4.41 A output in order to charge a 12 V battery,which is a significant amount of power loss.

Recent developments in switching converter technology include atechnique referred to as maximum power point tracking (MPPT), discussedin U.S. Pat. No. 6,844,739 to Kasai et al.

SUMMARY

In some embodiments, an apparatus includes a first node, a second node,and a power extractor. The power extractor includes power transfercircuitry to transfer power having a current between the first andsecond nodes, and power change analysis circuitry to detect a powerchange and a voltage change and to at least partially control amagnitude of the power being transferred in response to the detectedpower change and voltage change.

In some embodiments, an apparatus includes a first node, a second node,and power transfer circuitry to transfer power having a current betweenthe first and second nodes. Power analysis circuitry detects a powerchange and to increase the current as long as the power change show anincrease in power and to decrease the current as long as the powerchange shows a decrease in power.

In some embodiments, an apparatus includes a first node, a second node,and a power extractor including switching circuitry, power transfercircuitry, and power analysis circuitry. The power transfer circuitry isto transfer power having a current between the first and second nodes,wherein a magnitude of the current is at least partly responsive to aduty cycle of the switching circuitry. The power analysis circuitry isto detect a power change of the power and a voltage change and controlthe duty cycle responsive to the detected power change and voltagechange.

Other embodiments are described and claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description includes discussion of various figures havingillustrations given by way of example of implementations of variousembodiments of the inventions. The drawings should be understood by wayof example, and not by way of limitation.

FIG. 1 illustrates a prior art system for charging a battery orproviding power to another load using solar power.

FIG. 2 illustrates an array of power sources and power extractors toprovide power to a load according to some embodiments of the inventions.

FIG. 3 illustrates a system including a power source, power extractor,and load configured according to some embodiments of the inventions.

FIG. 4 illustrates impedance matching characteristics of a powerextractor as viewed from a power source according to various embodimentsof the inventions.

FIG. 5 illustrates the impedance matching characteristics of a powerextractor as viewed from a load according to various embodiments of theinventions.

FIGS. 6 and 7 each illustrate a system including a power source, powerextractor, and load according to some embodiments of the inventions.

FIG. 8 illustrates details of some embodiments of the system of FIG. 7.

FIG. 9 illustrates power change examples in connection with acurrent-voltage (IV) curve and a power curve.

FIG. 10 is a table illustrating operational concepts for a powerextractor according to various embodiments.

FIG. 11 illustrates two examples of a saw tooth wave and a switchingcontrol signal according to some embodiments.

FIGS. 12 and 13 are each a block diagram illustrating power slopedetection circuitry according to some embodiments.

FIG. 14 is a block diagram illustrating an example of an integratorcircuit that may be used in some embodiments.

FIG. 15 illustrates various connectors for connecting a power source anda load to a power extractor and/or a circuit board according to someembodiments.

FIG. 16 shows a circuit between a power source and a node according tosome embodiments.

FIG. 17 shows a diode between a power source and a node according tosome embodiments.

FIG. 18 illustrates an example of power transfer circuitry of FIG. 8.

FIGS. 19-22 each illustrate an example of power transfer circuitryaccording to some embodiments.

FIG. 23 illustrates a battery where the positive end of the battery isconnected to ground.

FIG. 24 illustrates comparison circuitry that may be used in someembodiments.

FIG. 25 illustrates a system including a power source, power extractor,and load according to some embodiments.

FIG. 26 illustrates processor control in connection with a loadaccording to some embodiments.

FIG. 27 illustrates two different battery loads connected to an outputnode by a switch according to some embodiments.

FIGS. 28 and 29 illustrate various details of a power extractoraccording to some embodiments.

FIG. 30 illustrates a power extractor coupled between one or morebatteries and a load according to some embodiments.

FIG. 31 illustrates a parallel configuration of batteries and powerextractors coupled to a load according to some embodiments.

FIG. 32 illustrates a side view of a integrated circuit including aphotovoltaic power source and a power extractor according to someembodiments.

FIG. 33 illustrates a top view of the integrated circuit of FIG. 32.

FIG. 34 illustrates a group of the integrated circuits of FIG. 32 in anarray.

FIGS. 35-37 each illustrate a group of PV cells or panels withcorresponding power extractors according to some embodiments.

FIG. 38 illustrates parallel groups of serial power extractors with eachgroup coupled to a power source according to some embodiments.

FIG. 39 illustrates parallel groups of power extractors with each powerextractor coupled to a power source according to some embodiments.

FIG. 40 illustrates power extractors and transmission lines according tosome embodiments.

FIGS. 41 and 42 illustrate a power extractor used in a device accordingto some embodiments.

FIG. 43 illustrates a system with a power extractor coupled between aregenerative generator and a battery according to some embodiments.

FIG. 44 illustrates a planar inductive device assembly using transformerclips.

FIG. 45 illustrates a system similar to that of FIG. 2 with a centralprocessor to gather data from or provide signals to the power extractorsaccording to some embodiments.

FIG. 46 illustrates a system with a power supply, power extractor, andcentral station to gather data from the power extractor or supplysignals to the power extractor according to some embodiments.

DETAILED DESCRIPTION

The following describes a DC-to-DC power extractor for providing powerfrom a power source to a load. The power extractor is called a power“extractor” because it operates in a way to obtain more power from apower source than typically would be obtained by the source without theoperation. In examples provided in this disclosure, the power extractoroperates to obtain impedance matching between the power source and thecombination of the power extractor and the load, and between the loadand the combination of the power source and the power extractor. This iscalled universal impedance matching because it occurs both as seen fromthe power source and as seen from the load. This impedance matchingallows the power source to provide a greater amount of power than itwould without the impedance matching. In some embodiments, discussedbelow, the power extractor is a power extraction switching converter.

In some embodiments, the impedance matching occurs as a consequence ofthe power extractor seeking a maximum power. In some embodiments, thepower extractor causes impedance matching by changing the duty cycle ofswitching circuitry coupled to power transfer circuitry of the powerextractor to cause increases in power until a maximum power is achieved.The changes to the duty cycle are made in response to detected powerchanges. In some embodiments, the power change is detected continuouslythrough analog circuitry, while in other embodiments the power change isdetected continuously through digital circuitry. In some embodiments,the detected power change includes a power slope, such as aninstantaneous power slope. When the detected power change is zero at atrue power maximum (not merely a local zero change), the powertransferred is at a magnitude (level or amount) that the power sourceprovides a maximum power given conditions beyond the control of thepower extractor. In some embodiments, maximum available power istypically very closely approached. Actually achieving maximum availablepower is an example very closely approaching it. Examples of suchconditions beyond the control of the power extractor that may apply forsome power sources include environmental conditions (e.g., amount of sunlight, temperature) and size of the power source (e.g., largerphotovoltaic cells or larger number of cells may provide more power). Ifthe power extractor's impedance is such that power is extracted at powerat too high of a current or too high of a voltage or too low of acurrent or too low of a voltage, the power source will provide less thana maximum amount of power. The maximum amount of power will be obtainedat a particular impedance. See FIGS. 9 and 10 and related discussion.

As used herein, a DC power source (called a power source herein),includes any source from which DC power might be generated and/orcaptured. Examples of DC power sources that may be used in accordancewith embodiments of the invention include, but are not limited to,photovoltaic cells or panels, a battery or batteries, and sources thatderive power through wind, water (e.g., hydroelectric), tidal forces,heat (e.g., thermal couple), hydrogen power generation, gas powergeneration, radioactive, mechanical deformation, piezo-electric, andmotion (e.g., human motion such as walking, running, etc.). Powersources may include natural energy sources and man-made power sources,and may be stable (providing an essentially constant power but variablein magnitude) and unstable (providing power that varies over time). Insome embodiments, the power sources include sub-power sources (e.g., asolar panel may multiple cells), while in other embodiments, the powersource is unitary. A disadvantage of using sub-power sources is thatthey might have different impedances and a single power extractor maymatch with the combined impedance, which may be less optimal than havinga separate power extractor for each power source. A “power source” mayalso be considered an “energy source.”

FIG. 2 illustrates a system including power sources 32, 34, and 36coupled to power extractors 42, 44, and 46, respectively. Power source32 and power extractor 42 form a power unit 52 and may be physicallyseparated as shown in FIG. 2 and adjacent as shown in other figures.Likewise, power sources 34 and 36 form power units 54 and 56. The outputof power extractors 42, 44, and 46 are joined at a node N2 andcumulatively provide power to node N2. Load 64 is also joined to nodeN2. Load 64 may include a single load or sub-loads such as a battery (orbatteries), an inverter and/or another sub-load or other load. NodesN1-1, N1-2, and N1-3 are between power sources 32, 34, and 36 and powerextractors 42, 44, and 46. Power units 52, 54, and 56 form a powerassembly 58. A power assembly may include more than three power units ormerely two power units. A load line 62 is illustrated. Unidirectionalprotection devices (e.g., diodes) may be used to prevent backflow ofcurrent to the power sources, but they are not required.

FIG. 3 illustrates a system with a power source 32 having an outputimpedance Z1 coupled through a conductor 60 and node N1 to powerextractor 42. Power extractor 42 is referred to as an impedance matcher,because as discussed above, in at least one mode of operation, itmatches impedances as discussed. In some embodiments, power extractor 42may operate in different modes. For example, in an ordinary operatingmode (called a first mode herein), power extractor 42 operates toimpedance match so that a maximum available power is provided by thepower source. When it is said that power extractor 42 “operates toimpedance match so that a maximum available power is provided” it isunderstood that, in practice, perfect impedance matching is typicallynot obtained and an absolute maximum available power is typically notobtained from the power source. Nevertheless, power extractor 42operates so as to seek perfect impedance matching or to approach perfectimpedance matching under closed-loop control including power analysiscircuitry 74 and described below. In some embodiments, under steadystate conditions, perfect impedance matching may be very closelyapproached.

Likewise, when it is said that the power transfer circuitry is totransfer the power at a magnitude to cause a power source to provide amaximum power available given conditions beyond the control of the powerextractor, it is understand the power source approaches the maximumpower under the closed-loop control of the power extractor. In someembodiments, that maximum available power is approached very closely.The power extractor may be said to seek to operate in a way to cause thepower source to provide a maximum available power. Approaching perfectimpedance matching or maximum power does not mean constantly movingcloser and closer to perfect matching or maximum power. Sometimes,changes in the input impedance cause the impedance matching to be closerto perfect (or optimal) impedance matching and sometimes changes in theinput impedance (or changes in the power source impedance) cause theimpedance to be further from perfect matching, but overall the controlloop causes a significant improvement in impedance matching compared towhat it would be without the control loop. Likewise, with approachingmaximum power.

In a protection mode (called a second mode herein), power extractor 42operates to protect itself and/or load 64 and/or source 32. Theprotective mode may be entered into in response to a limiting condition.Examples of limiting conditions are excessive voltage, power, or currentin the first node, power extractor, or second node; too little voltage,power, or current in the first node, power extractor, or second node;and a device limiting condition. In some embodiments, power extractor 42detects only a some of these limiting conductions to determine whetherto enter a protection mode. There may be additional modes and there maybe more than one type of ordinary operating mode and more than one typeof protection mode. For example, in at least one mode, power sourceconservation may be more important that achieve maximum power. This maybe the case, for example, if the power source is a battery (see theexample of FIG. 41).

Power extractor 42 includes power transfer circuitry 72 of FIG. 3between nodes N1 and N2 and provides output power to a load 64 through anode N2 and load line 62. For convenience of illustration, powerextractor 42 is shown as partially overlapping nodes N1 and N2. However,nodes N1 and N2 may be considered as being at the boundary of powerextractor 42, but note discussion of FIGS. 8 and 15. Load 64 has aninput impedance Z3. Power extractor 42 includes power analysis circuitry74 that analyzes the power and provides a switching circuitry controlsignal to control switching circuitry 78. Switching circuitry 78operates to at least partially control the operation of power transfercircuitry 72. Power extractor 42 includes an input impedance of Z2 andan output impedance of Z2*. When changes in power are detected, poweranalysis circuitry 74 responds by adjusting the timing (e.g., dutycycle) of switching circuitry 78. Switching circuitry 78 may also reactin a manner that seeks to maximize energy transfer efficiency through,for example, changing a frequency of switching of switching circuitry78.

FIGS. 4 and 5 illustrate the impedance matching characteristics of powerextractor 42 of FIG. 3. In FIG. 4, power source 32 has impedance Z1,called a first impedance in FIG. 4. Power extractor 42 has inputimpedance Z2 while load 64 has the impedance Z3. In FIG. 4, thecombination of Z2 and Z3 is called a second impedance. The impedance asseen by power source 32 when looking at the power extractor 42 is equalto its own impedance. In other words, power extractor 42 dynamicallymatches the impedance of power source 32 (i.e., Z1=Z2+Z3) so that thefirst and second impedances equal each other.

FIG. 5 illustrates that the impedance as seen by load 64 when looking atpower extractor 42 is also equal to its own impedance. In FIG. 5, thefirst impedance is Z1 and Z2* (the output impedance of power extractor42) and the second impedance is Z3. Load 64 sees output impedance Z2* onpower extractor 42. Thus, power extractor 42 also dynamically matchesthe impedance of the load (i.e., Z3=Z1+Z2*) so that the first and secondimpedances are matched. Given that the impedance of power extractor 42is typically different (Z2 or Z2*) depending whether the impedance ismeasured at N1 or N2, the impedances (Z2+Z3) as seen by the power sourceand (Z1+Z2*) as seen by the load may be thought of as virtualimpedances.

In some embodiments, whether power extractor 42 seeks to impedance matchwith power source 32 depends on whether load 64 can receive all thepower that power source 32 can provide. If load 64 can receive more thansource 32 can provide, then power extractor 42 seeks to have its inputimpedance match with the output impedance of power source 32, but doesnot necessarily seek to have its output impedance match with the inputimpedance of load 64. If load 64 can receive less than power source 32can provide, then power extractor 42 may go into a mode (possibly aprotection mode) in which it does not seek to have its input impedancematch with the output impedance of power source 32, but may seek tomatch its output impedance with the input impedance of load 64. If load64 can receive exactly or essentially exactly what source 32 canprovide, then power extractor 42 may seek to have its input impedancematch with the output impedance of power source 32 and its outputimpedance match with the input impedance of load 64. In otherembodiments, power extractor 42 may operate different. Impedancematching at the output node (node N2 in FIG. 3) may occur when powerextractors are connected together.

FIG. 6 illustrates a circuit 82 and a circuit 86 separated by a node N3in power transfer circuitry 72. Impedances of circuits 82 and 86 may becoadjutive (rendering mutual aid) and are modulated so that theaggregate impedance of power extractor 42 and load 64 is matched to theoutput impedance of power source 32. In some embodiments and situations,the aggregate impedance of power source 32 and power extractor 42 ismatched to the input impedance of load 64. Power is continuouslytransferred from power source 32 through circuit 82. The duty cycle ofS1 is dynamically adjusted to facilitate the virtual impedance matchingto the power source 32. Once the impedances are matched, the powerextracted from power source 32 is maximized. Likewise, power iscontinuously transferred from circuit 86 to load 64. The amount of powerdriven into load 64 is maximized when the impedance of circuit 86 ismatched with the impedance of load 64. A control loop 70 includes poweranalysis circuitry 74 and switching control circuitry 80. In someembodiments, control loop 70 is partly implemented with software. SwitchS1 is controlled by switching control circuitry 80. Power changeanalysis circuitry 74 detects changes in power from power source 32 atnode N1 and communicates with switching control circuitry 80. Switchingcontrol circuitry 80 controls, for example, the duty cycle of S1 so asto increase power as described below.

FIG. 7 illustrates another power transfer circuitry configuration thatmay be used in some embodiments of the invention. In FIG. 7, powertransfer circuitry 72 includes a circuit 84 between circuits 82 and 86,with node N3 between circuits 82 and 84 and node N4 between circuits 84and 86. Switching control circuitry 80 provides a switching signal(s) tocontrol switches S1 and S2. In some embodiments, the duty cycle of theswitching signal to S1 is the inverse of the duty cycle of the switchingsignal to S2. In other embodiments, the switching signals to S1 and S2are intentionally not inverses of each other. In some embodiments, theremay be additional switches. Circuits 82, 84, and 86 may be coadjutiveimpedances and are modulated by switches S1 and S2 under the control ofswitching control circuitry 80 such that the aggregate impedance ofpower extractor 42 and load 64 matches the output impedance of powersource 32, and the aggregate impedance of power source 32 and powerextractor 42 matches the input impedance of load 64. When the impedanceof power source 32 is matched with the combination of power extractor 42and load 64, circuit 72 is able to extract maximum power from powersource 32.

In some embodiments, circuit 84 transfers accumulated voltage potentialfrom N3 to N4 without interrupting the flow of power from circuit 82 tocircuit 86. Circuit 86 adapts its output impedance to facilitateimpedance matching with load 64. The duty cycle of S2 is dynamicallyadjusted to cause the impedance matching between circuit 86 and load 64.Thus, circuit 86 is able to transfer maximum power into load 64. Whilecircuit 86 is transferring power to load 64, circuit 82 continues tomatch its impedance with the impedance of power source 32 allowingmaximum power to be transferred from power source 32 through circuit 82.This process continues as S1 and S2 are alternately opened and closedaccording to the duty cycle of the switching signal. In someembodiments, the switch states of S1 and S2 are controlled by switchingcontrol circuitry 80 which receives the switching control signal frompower change analysis circuitry 74 based on the changes in poweravailable at N1. Alternatively, the power change detected can be a powerchange at a place other than node N1 such as node N2 or inside powerextractor 42.

FIG. 8 illustrates details that are included in some embodiments ofFIGS. 5 and 7, but other embodiments include different details.Referring to FIG. 8, power change analysis circuitry 74 includes powerchange detection circuitry 94 and other circuitry shown in otherfigures. Power transfer circuitry 72 includes circuits 82, 84, and 86.Circuits 82 and 84 include transformer T1 (including inductors L1 andL3) and transformer T2 (including inductors L2 and L4). Circuit 82includes capacitors C1 and C2 and a node N5 separating C1 and C2 andconnected to inductors L3 and L4. Power source is coupled to inductor L1through conductor 60 of node N1, an interface connector 110, and a nodeN1*. As an example, connector 110 may be a plug receptacle (see alsoFIG. 15). If the impedance difference between N1, connector 110, and N1*are relatively small, then they may be considered one node. Otherwise,they may be considered more than one mode. Likewise with node N2*,connector 112, and node N2. Inductor L1 is between nodes N1* and N3, andinductor L2 is between nodes N4 and N2*.

Power change detection circuitry 94 detects a power change of power atnode N1* and provides a switching control signal on conductor 98 to oneinput of comparison circuitry 80. In some embodiments, power changedetection circuitry 94 detects a slope of the power change and may becalled power slope detection circuitry 94 and provide a power slopeindication signal (as shown in FIG. 8). In some embodiments, the powerslope is an instantaneous power slope. Another input of comparisoncircuitry 106 receives a waveform such as a saw tooth wave from waveformgenerator circuit 102. Comparison circuitry 106 controls a duty cycle ofswitches S1 and S2. In some embodiments, S1 and S2 are not both open orboth closed at the same time (with the possible exception of brieftransitions when they are switching). Waveform generator circuit 102 andcomparison circuitry 106 are examples of circuitry in switching controlcircuitry 80.

When S1 is closed, electromagnetic fields change in T1 and T2 while theelectrostatic potential across C1 and C2 is altered and energy frompower source 32 is distributed electromagnetically into T1 and T2, whileelectrostatically in C1 and C2. When S1 opens, S2 closes and themagnetic flux in T1 begins to decrease. Thus, the energy stored in T1flows through N3 to capacitors C1 and C2 of circuit 84, depositing someof the energy as an electrostatic field onto C1 and C2, and some of theenergy into T2 of circuit 86 through node N5 and inductor L4. Theresidual flux in T2 also begins to decrease, transferring energy intothe load 64 through N2. When S1 closes and S2 opens again, the magneticflux in T1 begins to increase while the magnetic flux T2 also increasesas it consumes some of the electrostatic energy that was previouslystored onto C1 and C2. Thus energy stored in circuit 84 is dischargedand transferred to T2 and load 64.

Multi-phase energy transfer combines two or more phased inputs toproduce a resultant flux in a magnetic core equivalent to the angularbisector of the inputs. (Note: an angle bisector of an angle is known tobe the locus of points equidistant from the two rays (half-lines)forming the angle.) In this embodiment of the power extractor,capacitors C1 and C2 are used to shift the phase of the current that isapplied to the secondary winding of T1 and T2 (L3 and L4 respectively).Thus, multi-phased inputs are applied to the cores of T2 and T3. Thesummation of the multiphase inputs alter the electromotive force thatpresent during the increase and reduction of flux in the transformersprimary windings L1 and L3 The result is the neutralization (within thebandwidth of the operational frequency of the power extractor) of highfrequency variations in the reactive component of the impedance thatcircuits 82 and 86 exhibit to the source and load respectively. Circuits82 and 86 may be multiphase bisector energy transfer circuits to causethe multiphase bisector energy transfer and to interface with circuit84.

Due to the dynamic properties of circuit 82, power source 32 “sees” anequivalent impedance at inductor L1 power extractor 42. Likewise, withinductor L2 and load 64. The input and output impedances of powerextractor 42 are adjusted by controlling the duty cycle of S1 and S2.Optimal matching of impedances to the power source 32 occurs whenmaximum power extraction from the power source is achieved.

Power slope detection circuitry 94, power change indication signal, andcomparison circuitry 106 are part of a control loop that controls theduty cycle of switching circuitry 78 to achieve maximum power extraction(i.e., ΔP/ΔV=0) from power source 32. The control loop may also controlthe switching frequency of switching circuitry 78 to influence theefficiency of power transfer through the power transfer circuitry 72.Merely as an example, the frequency may be in the range of 100 KHz to250 KHz depending on saturation limits of inductors. However, in otherembodiments, the frequencies may be substantially different. The sizeand other aspects of the inductors and associated cores and othercomponents such as capacitors can be chosen to meet various criterionincluding a desired power transfer ability, efficiency, and availablespace. In some embodiments, the frequency can be changed by changing thefrequency of the waveform from waveform generator circuit 102. Otherfigures show a control of circuit 102. In some embodiments, thefrequency is controlled by a control loop as a function of whether anon-time rise of current is between a minimum and maximum current in aenergy transfer circuit.

As used herein, the duty cycle of switching circuitry 78 is the ratio ofthe on-time of S1 to the total on-time of S1 and S2 (i.e., dutycycle=S1/(S1+S2)). The duty cycle could be defined by a different ratioassociated with S1 and/or S2 in other embodiments. When the voltages ofpower source 32 and load 64 are equal and the duty cycle is 50%, thereis zero power transfer through power extractor 42 in some embodiments.If the voltages of power source 32 and load 64 are different, a higheror lower duty cycle may cause zero power transfer through powerextractor 42. In other words, a particular duty cycle of switchingcircuitry 78 is not tied to a particular direction or amount of powertransfer through power transfer circuitry 72.

As noted, the power change can be continuously detected and theswitching control signal (of FIGS. 7, 8, and 11) can be continuouslyupdated. Using analog circuits is one way to perform continuousdetection and updating. Using digital circuits (such as a processor) isanother way to perform continuous detection and switching control signalupdating. Even though the updating from some digital circuits may insome sense not be exactly continuous, it may be considered continuouswhen for all practical purposes it produces the same result as trulycontinuous updating. As an example, the updating of the switchingcontrol signal is also considered continuous when the frequency ofchange is outside the control loop bandwidth. In some cases, theupdating of the switching control signal also could be consideredcontinuous when the frequency of change is within the control bandwidth.Merely as an example, in some implementations, the control loopbandwidth may be around 800 Hz. In other embodiments, the control loopbandwidth is higher than 800 Hz, and perhaps much higher than 800 Hz. Instill other embodiments, the control loop bandwidth is lower than 800 Hzand depending on the desired implementation and performance may be lowerthan 400 Hz.

FIG. 9 illustrates an example of a typical current-voltage (I-V) curveand a power curve. Many power sources (e.g., a solar panel) produce arelatively constant current at different voltages. However, when thevoltage reaches a certain threshold in these power sources, the currentbegins to drop quickly. The threshold voltage corresponds to a kneeregion in the I-V curve. The maximum power point (P_(max)) alsocorresponds to the knee region in the I-V curve.

FIG. 10 is a table illustrating operational concepts for power extractor42 according to various embodiments. Example (1), shown as arrow (1) onFIG. 9, shows that when power and voltage are both increasing, theoperating point of the power extractor is on the left side of P_(max).When operating on the left side of P_(max), too much current is beingdrawn by power extractor 42 from power source 32 and, accordingly, powersource 32 is providing less than a maximum available power from powersource 32. The maximum available power is the most amount of power thatcould be achieved given environmental conditions and other conditionsbeyond the control of power extractor 42. In order to reduce currentflow, the duty cycle of switching control circuitry 78 is decreased.This is also the case with example (2) in which arrow (2) shows thatwhen power and voltage are both decreasing, there is also too muchcurrent and less than a maximum available power from power source 32.Conversely, when operating on the right side of P_(max) (examples (3)and (4)), too little current is being drawn by the power extractor andless than a maximum available power from power source 32. Thus, in orderto increase the current flow, the duty cycle of switching controlcircuitry 89 is increased. FIGS. 9 and 10 illustrate a specificationimplementation under particular conditions. Other implementations mayoperate differently and involve additional factors. In a differentimplementation, the current could be increased by decreasing the dutycycle.

Referring again to FIG. 9, if the power is at Pmax for a length of time,then the power and voltage is neither increasing nor decreasing for thatlength of time. Accordingly, the duty cycle may remain the same. In someembodiments, the control loop includes mechanisms to prevent a localpower maximum (local minimum slope) that is not a true maximum powerfrom being interpreted as a power maximum so the duty cycle is notchanged. One mechanism is the natural noise that will tend to causecontrol loop fluctuations resulting in the power change. Anothermechanism is artificially induced control loop fluctuations that in someimplementations may result in the duty cycle changing after a particularamount of time if the detection circuitry shows no change in power orvoltage.

Power slope detection circuitry 94 creates the switching control signalin response to the situation of FIG. 10. FIG. 11 illustrates howcomparison circuitry 106 compares the switching control signal with thesaw tooth waveform. The duty cycle of switching control circuitry 78changes as the area of the saw-tooth wave above the switching controlsignal changes. For example, the area of the saw-tooth wave above theswitching control signal is smaller from time t₃ to t₄ than from time t₁to t₂. The smaller area above the switching control signal correspondsto a lower duty cycle. The smaller area above the switching controlsignal could correspond to a higher duty cycle in other embodiments. Thevoltages 0.5 V1 and 0.6 V1 are used for purposes of illustration and arenot limiting. Additionally, in other embodiments, other waveforms(triangle, sine, etc.) could be used in place of the saw-tooth wave.

FIGS. 12 and 13 illustrate examples of power slope detection circuitry94 that may be used in some embodiments of the invention. There arevarious other ways to implement the same or similar functions. In FIG.12, a current measuring circuit 128 includes voltage measuring circuitry130 internal to power slope detection circuitry 94 to measures thevoltage across a small resistor Rs at N1 (or at another location) todetermine the current (I=V/R). Although a small resistor Rs is shown,there are various other ways to measure current including throughmeasuring a magnetic field. The voltage-level signal from N1 (i.e., VN1)(or at another location) and the current-level signal from N1 (i.e.,IN1) (or at another location) are continuous signals. (In otherembodiments, the voltage is deduced indirectly.) Multiplier 134continuously multiplies the voltage and current at N1 to determine thepower at N1 (PN1).

Differentiator 136 provided a signal responsive to changes in power (ΔP)while processor 132 provides a signal responsive to changes in voltage(ΔV). In some embodiments, differentiator 136 measures the power slope.ΔP/ΔV represents the slope power at node N1 (or the other location).Maximum power is achieved when ΔP/ΔV=0. The slope of the power (ormerely power change) can be determined in various ways. The power slopemay be an instantaneous power slope determined through analog circuitry.Alternatively, a power slope or merely a power change can be detectedthrough digital circuitry such as a processor by comparing samples. Theprocessor could compare samples and determine a slope and acorresponding change in voltage (or a voltage slope). Alternatively, theprocessor could merely determine whether the power is increasing ordecreasing and whether the corresponding voltage is increasing ordecreasing. In some embodiments, differentiator 136 merely provides amagnitude of the power change (power slope) and in other embodiments, itprovides both a magnitude and a direction. For example, the slope atpoint (1) in FIG. 9 is positive in direction while the slope at point(2) is negative in direction despite having a similar magnitude.

Power slope detection circuitry 94 includes voltage change detectioncircuitry 132, which may be a processor, application specific integratedcircuit (ASIC), or other circuitry. Circuitry 132 may also performscaling as discussed. In some embodiments, circuitry 94 detects a slopeof voltage change and in other embodiments, and in other embodiments, itmerely detects whether the voltage is increasing or decreasing. It maydetect the change through analog or digital circuitry. In someembodiments, only the direction (i.e., not the magnitude) of the voltagechange is relevant. Referring again to FIG. 9, example (1) involves anincreasing voltage (positive) while example (2) involves a decreasingvoltage (negative). Thus, in example (2) of FIG. 10, when differentiator136 indicates a decrease in power, voltage change detection circuitry132 indicates a decrease in voltage. When there is a decrease involtage, controlled inverter 138 inverts the negative output ofdifferentiator 136, which results in a positive number corresponding tothe positive power slope at point (2). Thus, by combining the results ofdifferentiator 136 and voltage change detection circuitry 132, powerslope detection circuitry 94 can determine whether to increase ordecrease the current. As shown in FIG. 10, when the power slope ispositive (examples (1) and (2)), the duty cycle of switching circuitry78 is decreased; when the power slope is negative (examples (3) and (4),the duty cycle is increased. In some embodiments, the output ofcontrolled inverter 138 is scaled by a scalar (amplifier A1) 140, whichputs the signal in a proper range to be compared with the waveform (asshown in FIG. 11). Further, in some embodiments, an integrated 144 maybe used to act as a low pass filter and smooth out otherwise rapidchanges.

In some embodiments, the switching control signal is dependent on thesteepness of the power slope or amount of power change, and in otherembodiments, the changes are incremental. In some embodiments, circuitry94 does not model a power curve, it merely responds to detected voltageand current changes to move toward the maximum power, without beingaware of where the maximum power on a curve. Indeed, it is not necessaryto know what the power curve would look like. In other embodiments,circuitry 94 or other circuitry such as processor 172 in FIG. 25 modelsa power curve.

In some embodiments, the input (e.g., voltage and/or current) and thecontrol loop may define the saturation limit for each of the inductorsin power transfer circuitry 72. In other words, the saturation limit ofeach of the inductors may be independent of the power extractor outputand switching frequency.

FIG. 13 shows how changes in voltage can be detected by analog detectioncircuitry 148 (e.g., differentiator, etc) in some embodiments.Additionally, an external current sensor 146 can measure the amount ofcurrent being transferred by the power extractor and communicate thatinformation to power slope detection circuitry 94. Amplifier 140 canalso be controlled by a processor, ASIC, or FPGA 150 based on variousconditions including but not limited to weather conditions, and chargelevel of the load (e.g., battery).

FIG. 14 illustrates an example of the optional integrator 144 of FIGS.12 and 13. Integrator 144 may be included in some embodiments of powerslope detection circuitry 94 to dampen the switching control signal frompower slope detection circuitry 94. Integrator 144 includes a resistorR1 at the input of an op amp 152 and a resistor R2 in parallel with acapacitor C. Charge stored in the capacitor is “bled off” by resistorR2. The bleeding off of charge by resistor R2 causes the output ofintegrator 144 to be lower over time than the input (as received frompower slope detection circuitry). This reduced output reduces the impact(i.e., dampens) of switching control signal on the duty cycle ofswitching circuitry 78.

There are various other ways to obtain the switching control signal.Examples include doing all the analysis in a processor. Other examples,involve considering the saturation levels of the inductors. An exampleis illustrated in connection with FIG. 28. A phase-locked loop (PLL) maybe used to detect on and off times of switches S1 and S2. Thisinformation could be provided to the processor which may use theinformation for various purposes. Two phase related signals may be usedin connection with controlling the duty cycle.

FIG. 15 shows several connectors (110, 112, 116, 118, 122, and 124) forconnecting power source 32 and load 64 to power extractor 42 and/or acircuit board 156 as shown. Circuit board 156 may be in a housing 158.Circuit board 156 and housing 158 may be in a wide variety of formsincluding, for example, a stand alone box. Alternatively, circuit board156 could be in a consumer electronics device (e.g., cell phone,personal data assistant (PDA)) or be a computer card in which case theload could be integrated in the housing as well, or in a variety ofother implementations. As described below, in some implementations, thepower source could be integrated with the housing. If the connector hasa substantially different impedance than the surrounding nodes, then thedifferent nodes (e.g., N1, N1*, N1**) can be considered separate nodes.If the connector has a relatively little impedance than the surroundingnodes, then the different nodes can be considered one node.

FIG. 16 shows that a circuit 160 can be included between power source 32and node N1 in some embodiments. FIG. 17 shows that a diode 162 can beincluded between power source 32 and N1 in some embodiments.

FIG. 18 reproduces the power transfer circuitry of FIG. 8 forconvenience of comparison with alternative power transfer circuitryillustrated in FIGS. 19-22. The values of the resistors, capacitors andinductors (such as R1, R2 C1, C2, C3, C4, L1, L2, L3, L4, L5, and L6)are not necessarily the same in FIGS. 18-22.

FIG. 23 illustrates a battery 164 of which the positive end of thebattery is connected to ground. N2 represents the node at the output ofpower extractor 42. In some embodiments, a battery 164 is connected toN2 such that the negative end of battery 164 is tied to N2 and thepositive end is tied to ground. Referring to FIGS. 7 and 8, one reasonto have the arrangement of FIG. 23 is that, in some embodiments, thevoltages at N4 and N3 have opposite polarities. For example, if thevoltage at N3 and N4 are VN3 and VN4, respectively, VN3 may be −VN4. Inother embodiments, battery 164 can be connected such that the positiveend is tied to N2 and the negative end is tied to ground. Further, insome embodiments, the voltage at N4 and N3 are not opposite voltages.

FIG. 24 illustrates an example of comparison circuitry that may be usedin some embodiments of the invention. Comparison circuitry 106 can beany circuitry used to compare power change indication signal 98 with areference signal (e.g., a voltage reference, V_(ref)) in order toregulate the duty cycle of the switching circuitry.

FIG. 25 is similar to FIG. 8, but includes additional circuitryincluding a processor/ASIC/and/or field programmable gate array (FPGA)172 (hereinafter processor 172), scaling circuitry 176, current sensors184, 186, and 188. Processor 172 receives signals indicative of thesensed current as well as voltage of node N1*. Letters A and B showconnections between current sensors 184 and 186 and processor 172. Insome embodiments, processor 172 also gathers information and/or providescontrol to sub-loads inverter 64-1, battery 64-2, and/or other load 64-3of load 64. The current information can be used to indicate suchinformation as the rate, amount, and efficiency of power transfer. Onereason to gather this information is for processor 172 to determinewhether to be in the protection mode (such as the second mode) or theordinary operating mode (such as the first mode). In a protection mode,there are various things processor 172 can do to provide the powerextractor 42 or load 64. One option is to open switch S3. Another optionis to open a switch S4 shown in FIG. 26. Another option is to provide abias signal to scaling circuitry 176 which is combined in circuitry 178with a power slope indication signal to create the switching controlsignal on conductor 98. For example, if the bias signal causes theswitching control signal to be very high, the duty cycle would be lowcausing the current to be small. The regulation of power in theprotection mode can be to completely shut off the power or merely toreduce the power. In the protection mode, the goal is no longer tomaximize the power transferred. In some embodiments, the bias signal isasserted for purposes other than merely protection mode.

FIG. 26 illustrates a processor control line to control a switch, S4,which can be opened to shut off any power transfer from power extractor42 to a load (e.g., inverter 64-1, battery 64-2, and/or other load64-3). Processor 172 also controls the routing of power betweendifferent sub-loads (e.g., inverter 64-1, battery 64-2, or other load64-3) in some embodiments. Furthermore, temperature sensors 192-1,192-3, and 192-3 are shown as being connected to different loads. Basedon the temperature (e.g., too much heat), the processor can cause switchS4 to open or close or otherwise regulate power, such as through thebias signal or opening switch S3. Power extractor 42 can operate in aprotective mode based on any device limiting condition. Examples ofdevice limiting conditions include one or more of the following:excessive heat, voltage, power, or current in N1, power extractor 42,and/or N2. There may be other device limiting conditions. The powerextractor may sense the state of external switches such as dip switchesor get updates through a memory (such as a flash memory) to determineload characteristics that may be considered in deciding whether to enterinto a protective mode.

FIG. 27 illustrates two different battery loads, 64-1-1 and 64-1-2,connected to output node N2 by a switch, S5. This configurationillustrates the functional flexibility of power extractor 42 in variousembodiments. Given both the source-side and load-side impedance matchingcharacteristics, power extractor 42 automatically adapts to the load andprovides power to the load. In other words, the output of powerextractor 42 is power—the output voltage and the output current thatcomprise the power are not fixed. The output voltage and output currentautomatically adapt to the load, without reducing the power. In otherwords, power extractor 42 may operate independent of any voltage. Thus,the output power may be unregulated, with the exception of theprotection mode.

For example, in some embodiments, power extractor 42 might extract 60Watts of power from power source 32 to be transferred to battery 186-1.If battery 64-2-1 is a 12 Volt battery, then power extractor 42 mightprovide 5 A of current at 12 Volts to charge the battery. If battery64-2-1 is switched to or swapped for a 15 Volt battery 64-2-2, thenpower extractor 42 will still provide 60 Watts of power to charge thebattery in the form of 4 A of current at 15 Volts. While this exampleillustrates the adaptability/flexibility of power extractor 42, itshould be noted that the output voltage from power extractor 42 may needto be slightly higher than the battery voltage in order to cause currentto flow into the battery.

In the above example, and in some other embodiments, the power extractorfeedback point may be based on output power transfer, rather thantraditional systems where the feedback point is based on output voltageor current. Other embodiments operate differently.

FIG. 28 illustrates further detail of power extractor 42 according toother embodiments. Current sensors 222 and 224 provide signalsindicative of the current through switches S1 and S2, which are summedin summer 202. Power may be related to the average current from summer202. These may be provided to an integrator 206 to provide an signalindicative of the power, which is differentiated by differentiator 212and amplified by amplifier 214. Voltage change (or voltage slope) may beconsidered as mentioned above.

FIG. 29 illustrates voltage regulators 232 and 236 which takeunregulated voltage from power extractor 42 and provide a regulatedvoltage as needed (e.g., to power various circuits within powerextractor 42). The unregulated power is provided to regulator 232through a transformer T2 (inductors L5 and L6) and diode D1. Theunregulated power is provided to regulator 236 through a transformer T4(inductors L7 and L8) and diode D2.

Power extractor 42 may be used in transferring power from one or morebatteries 272 to a load 64 which may include another battery. FIG. 30illustrates a battery or batteries 272 as being the power source. Areason to use power extractor 42 with batteries as the source is thatthe batteries with lower power and a lower voltage can be used to chargeother batteries including with a higher or lower voltage. Given thatpower extractor 42 extracts DC power in whatever form it is available(e.g., not at specific or fixed voltage or current) and outputs power inwhatever form needed by the load (e.g., not at a specific or fixedvoltage or current), power extractor 42 is flexible and adaptable—withinsafety or other reasonable limits, there are no restrictions as to whattype of source and/or load can be connected to power extractor 42. Forexample, power extractor 42 can transfer the available power in a 9 Voltbattery to charge a 15 Volt battery. In another example, power extractor42 can transfer power from two 5 Volt batteries to a 12 Volt battery.The flexibility and adaptability of power extractor 42 is in contrast totraditional charge controllers and other power transfer systems wherepower transfer from input to output is a byproduct of output voltageregulation. FIG. 31 illustrates parallel power extractors 42 and 44receiving power from battery power sources 276 and 278, respectively,and providing power to load 64.

FIG. 32 illustrates a side view of an integrated circuit chip (IC1)including a photovoltaic power source 284 and power extractor 286fabricated onto a substrate 282 of IC1. Power extractor 286 may be thesame as or somewhat different than power extractor 42. FIG. 33 shows atop view of IC1 including photovoltaic power source 284, power extractor286, first and second nodes and a chip interface 288. There may be adiode between power extractor 286 and source 284. In practice, thelayout could be somewhat different with photovoltaic power source 284taking up more or less service area than is shown. Likewise, powerextractor 286 could take up more or less area than is shown. FIG. 34shows a plurality of IC chips IC1, IC2, . . . IC25 similar to IC1 ofFIGS. 32 and 33 joined by a frame 296. The integrated circuit may alsocontain various function circuitry in addition to the power extractorand the power source. FIG. 32 illustrates that the power extractor canbe on a very smaller scale. Conversely, power extractor 42 may be on avery large scale, for example, in high power embodiments. FIG. 40 may bean example of such high power embodiments. For example, parts of thecontrol loop such as power slope detection circuitry 94 may be up to asubstantial distance from node N1. In some embodiments, the distance isless than one meter, and in other embodiments, it is more than one meterand it may be substantially more than one meter. Alternatively, thepower slope detection circuitry and power transfer circuitry may beclose together in the same container or housing. Optical coupling ormagnetic coupling may be used in various places including between nodeN1 and the power change detector.

FIGS. 35, 36, and 37 illustrate different configurations for connectingone or more power extractors (power extractors 1, 2, and 3) to one ormore photovoltaic (PV) sources according to various embodiments. Forexample, in FIG. 35, PV power sources (e.g., PV cells or PV panels) aredirectly connected together and to power extractors 1, 2 and 3, throughconnectors 320-1, 320-2, and 320-3, and 322-1 and 322-2, which may beglues, adhesives, mounting brackets, and/or other connectors in variousembodiments. In FIG. 36, PV sources 1, 2, and 3 and power extractors 1,2, and 3 are directly connected while the entire unit is supported by anexternal frame 320. In FIG. 37, PV sources are connected to each otherand to power extractors 1, 2, and 3 via frame elements 330, 334-1,334-2, 338-1, 338-2, and 228-3.

FIGS. 38 and 39 illustrate various configurations for connectingmultiple power sources and multiple power extractors according tovarious embodiments. For example, FIG. 38 shows power extractors PE11,PE12, and PE13 in series to increase voltage from a power source S1.Parallel power extractors PE21, PE22, and PE23 in series with powersource PS2, and PE31, PE32, and PE33 in series power source PS3 arecombined to increase current. FIG. 39 is similar, but each powerextractor is coupled to a power source (PS11 to PE11, PS12 to PE12, PS13to PE13, PS21 to PE21, PS22 to PE22, and PS23 to PE23).

FIG. 40 illustrates the placement of power extractors in one or moretransmission lines. Of course, the magnitude of the power that may betransferred through power extractors 1, 2, and 3 in FIG. 40 is fargreater than may be transferred in the integrated circuit of FIGS.32-34.

The power extractor of the invention may be used in connection with manydifferent types of devices. For example, FIG. 41 illustrates the use ofa power extractor 358 in a device 350 such as a pacemaker. A pacemakerdevice is used in this example by way of illustration only; other typesof devices may be similarly be used in other embodiments. Powerextractor 358 extracts power from battery or batteries 354 for power fora load 312 (e.g., the pacemaker itself). Power extractor 358 includes aprocessor/ASIC/or other circuitry 360 to determine battery usage and/orbattery life in the pacemaker. The information can be communicatedthrough an antenna 366. Based on that information, a doctor ortechnician or other person can send control information to processor 360to bias the power extractor such that battery power is conserved,optimized, etc. in device 302 as desired. That is, it is not necessarilydesirable to use the battery with the most power, but ratherconservation of power may be more desirable. The bias signal of FIG. 25may be useful for helping with battery conservation.

FIG. 42 illustrates the use of a power extractor 388 in another device382, such as a cell phone. Again, a cell phone is used by way of exampleand illustration; other devices may incorporate a power extractor insimilar fashion. Power extractor 388 is included in device 382 toextract power from a power source 384. Example sources of power caninclude light (including solar) power, heat (e.g., body heat), energyfrom motion (e.g., walking, running, general body movement, etc.), wind,battery, converting infrared to electrical energy, etc. Any electricalpower that can be generated by power source 384 can be extracted bypower extractor 388 and transferred to load 392 to power device 382.Processor 390 may be used control a desirable mode, for example, gettingthe maximum power out of a solar cell or thermal couple power source, ortrying to converse battery power when the battery gets low. The devicecould have a combination of power sources. Thus, in some embodiments,power extractor 388 can be used to charge, either partially or fully, acell phone battery without having to plug device 382 into a traditionalelectrical outlet.

As another example, FIG. 43 illustrates a vehicle wheel 404 with aregenerative brake generator 408 which provides power to power extractor418 to charge a battery 418. Power extractor 418 may seek to get themaximum power out of generator 408.

FIG. 44 illustrates transformer clips 512-1, 512-2, 512-3, and 512-4that may be used to provide cooling for planar inductive devices suchplanar inductance coils or planar transformers including I-cores 514-1,514-2, 514-3 and 514-4 and E-cores 518-1, 518-2, 518-3, and 518-4supported by a printed circuit board (PCB) fabrication 520 placed in achassis 522. Chassis 522 may be attached on a backside of a solar cell,solar panel, or other power source. Clips 512 may be made of aluminum,copper, or some other thermally conductive material. A thermal heatpaste or other heat conductor may be used to help with heat conduction.Of course, the system of FIG. 44 is not be used in many embodiments.

FIG. 45 is similar to FIG. 2 except that a processor 484 communicateswith power extractors 42, 44, and 46. The communication may be in justone or in both directions. Examples of the data or other informationcommunicated are provided in connection with FIG. 46. Memory 488 canhold data for future analysis.

FIG. 46 illustrates a system with a power source 550 to provide power toa power extractor switching converter (PESC) 552 which may be the sameas power extractor 42. In addition to controlling PESC functions, aprocessor (such as a microprocessor or digital signal processor) in PESC552 may collect statistical information about all stages of the powerconversion and communicates real time telemetry, power statistical data,and energy statistical data to a central station and also receives realtime data power control algorithms, administrative information, sensormanagement commands, and new software images from the central station.The gathered information (including one or more of the following:status, statistics, power extractor configuration, GPS (globalpositioning system) information, and environmental information) isprovided by the processor in PESC 552 to a processor in a centralstation 564 through wired or wireless (560) communication. Processor 484and memory 488 of FIG. 45 are examples of components of central station564. A communication subsystem (for example, Ethernet) allows thecommunication between the processor and the central station 564. Theprocessor in PESC 552 may include input line side DC voltage and currentsensors, power stage output voltage and current sensors, output side DCsignal sensing and output line side DC sensors.

Various additional components may be used in the above-illustratedcomponents. For example, a fuse and blocking diode may be placed inparallel with a load. If the fuse is blown because the diode is forwardbiased, it may be used to provide information that there was excessivecurrent or voltage. The information may be of immediate use to place thesystem in a protective mode or it may be of use for later diagnosticinformation. A fuse may also be in series between the extractor and theload.

In some embodiments, circuitry such as a thermocouple device may be usedto recapture heat from the power extractor and create power from it.

In some embodiments, the power may be delivered in discrete packets.

The background section of this disclosure provides various detailedinformation which is believed to be correct, but which may inadvertentlyinclude some errors. These errors, if they exist, would in no waydetract from the inventions described and claimed herein. The DetailedDescription section may also include some inadvertent errors which wouldnot detract from the invention. Further, the Detailed Descriptionsection includes some theoretical explanations of the operation of theillustrated power extractor. It is believed that these theoreticalexplanations are correct, but if they are partially incorrect that wouldnot detract from what is an enabling disclosure or detract from theinventions described and claimed.

It will be appreciated that the figures include block diagrams andschematic representations that may be implemented in a variety of waysand that actual implementations may include various additionalcomponents and conductors.

As used herein, the term “embodiment” refers to an implementation ofsome aspect of the inventions. Reference in the specification to “anembodiment,” “one embodiment,” “some embodiments,” or “otherembodiments” means that a particular feature, circuitry, orcharacteristic is included in at least some embodiments, but notnecessarily all embodiments. Different references to “some embodiments”do not necessarily refer to the same “some embodiments.”

When it is said the element “A” is coupled to element “B,” element A maybe directly coupled to element B or be indirectly coupled through, forexample, element C. When the specification or claims state that acomponent, feature, circuit, structure, process, or characteristic A isin response to a component, feature, circuit, structure, process, orcharacteristic B, it merely means that A is at least partiallyresponsive to B (but may also be responsive to C, or B and C at the sametime). That is, when it is said A is in response to B, A could be inresponse to B and C at the same time. Likewise, when it is said that Acauses B, A is at least a partial cause of B, but there could be othercauses of B either separately or in combination with A.

If the specification states a component, feature, structure, circuitry,or characteristic “may”, “might”, or “could” be included, thatparticular component, feature, circuitry, or characteristic is notrequired to be included. If the specification or claim refers to “a”structure, that does not mean there is only one of the structure.

Besides what is described herein, various modifications may be made tothe disclosed embodiments and implementations of the invention withoutdeparting from their scope. Therefore, the illustrations and examplesherein should be construed in an illustrative, and not a restrictivesense. The scope of the invention should be measured with reference tothe claims that follow.

What is claimed is:
 1. An apparatus comprising: a first node to coupleto a power supply to supply power; a second node to couple to a load toreceive power; and a power extractor including: power transfer circuitryto transfer power having a current to the second node based on powersupplied at the first node, power change analysis circuitry to detect aninstantaneous power change and a voltage change at the first node, andat least partially control the current of the power to be transferred inresponse to the detected instantaneous power change and voltage changeat the first node, the current to the second node to decrease when thepower change and the voltage change at the first node are bothincreasing, and when the power change and the voltage change at thefirst node are both decreasing, and increase when the power change atthe first node is decreasing and the voltage change at the first node isincreasing, and when the power change at the first node is increasingand the voltage change at the first node is decreasing, switchingcircuitry to control the power transfer circuitry; and switching controlcircuitry to control a duty cycle of the switching circuitry, whereinthe power change analysis circuitry operates in different modes andwherein in an ordinary operating mode, under some conditions, the poweranalysis circuitry causes the power transfer circuitry to increase thecurrent of the power to be transferred by decreasing the duty cycle ofthe switching control circuitry, and decrease the current of the powerto be transferred by increasing the duty cycle of the switching controlcircuitry.
 2. The apparatus of claim 1, wherein the power extractorfurther includes: switching circuitry to control the power transfercircuitry; and switching control circuitry to control a duty cycle ofthe switching circuitry, wherein the power change analysis circuitryoperates in different modes and wherein in an ordinary operating mode,under some conditions, the power analysis circuitry causes the powertransfer circuitry to decrease the current of the power to betransferred by decreasing the duty cycle of the switching controlcircuitry, and increase the current of the power to be transferred byincreasing the duty cycle of the switching control circuitry.
 3. Theapparatus of claim 2, wherein the power transfer circuitry includes afirst energy transfer circuit connected to the first node tocontinuously transfer energy, a second energy transfer circuit connectedto the second node to continuously transfer energy, and an intermediateenergy transfer circuit connected between the first and second energytransfer circuits to discontinuously transfer energy between the firstand second energy transfer circuits.
 4. The apparatus of claim 3,wherein the switching circuitry is to modulate voltages at a third nodebetween the first and intermediate energy transfer circuits, and at afourth node between the intermediate and second energy transfercircuits.
 5. The apparatus of claim 3, wherein a frequency of operationof the switching circuitry is dynamically adjusted to maximizeefficiency of power transfer between the first and second nodes.
 6. Theapparatus of claim 3, wherein the first and second energy transfercircuits each includes an inductor and the intermediate energy transfercircuit includes capacitors.
 7. The apparatus of claim 3, wherein thefirst, second, and intermediate energy transfer circuits each include atleast one capacitor.
 8. The apparatus of claim 1, wherein the powertransfer circuitry includes a first energy transfer circuit connected tothe first node to continuously transfer energy, a second energy transfercircuit connected to the second node to continuously transfer energy,and an intermediate energy transfer circuit connected between the firstand second energy transfer circuits to discontinuously transfer energybetween the first and second energy transfer circuits.
 9. The apparatusof claim 8, wherein the switching circuitry is to modulate voltages at athird node between the first and intermediate energy transfer circuits,and at a fourth node between the intermediate and second energy transfercircuits.
 10. The apparatus of claim 8, wherein the first and secondenergy transfer circuits each includes an inductor and the intermediateenergy transfer circuit includes capacitors.
 11. The apparatus of claim8, wherein the first, second, and intermediate energy transfer circuitseach include at least one capacitor.
 12. The apparatus of claim 1,further comprising a power source to provide power to the first node andpower analysis circuitry seeks to control the duty cycle of theswitching circuitry to maximize power transfer through the powertransfer circuitry given conditions beyond the control of the poweranalysis circuitry and given inefficiencies of the apparatus.
 13. Theapparatus of claim 12, wherein the power source is a photovoltaic powersource and one of the conditions beyond the control of the poweranalysis circuitry is an amount of sunlight on the power source.
 14. Theapparatus of claim 12, wherein there is at least one intermediate nodebetween the power source and the first node.
 15. The apparatus of claim1, further comprising a load coupled to the second node.
 16. Theapparatus of claim 1, wherein the power change analysis circuitry is todetect a power slope and a voltage slope.
 17. The apparatus of claim 1,wherein the power extractor operates to seek to match an input impedanceof the power transfer circuitry with an output impedance of a powersource.
 18. The apparatus of claim 1, the power change analysiscircuitry to further filter rapid power changes and voltage changes atthe first node.
 19. An system comprising: a power source; a load; and apower extractor coupled to the power source and the load, the powerextractor to include: power transfer circuitry to transfer power havinga current between the power source and the load, power change analysiscircuitry to detect an instantaneous power change and a voltage changeat the power source and at least partially control the current of thepower to be transferred in response to the detected instantaneous powerchange and voltage change at the power source, the current to decreasewhen the power change and the voltage change at the power source areboth increasing, and when the power change and the voltage change at thepower source are both decreasing, and increase when the power change atthe power source is decreasing and the voltage change at the powersource is increasing, and when the power change at the power source isincreasing and the voltage change at the power source is decreasing,switching circuitry to control the power transfer circuitry; andswitching control circuitry to control a duty cycle of the switchingcircuitry, wherein the power change analysis circuitry operates indifferent modes and wherein in an ordinary operating mode, under someconditions, the power analysis circuitry causes the power transfercircuitry to increase the current of the power to be transferred bydecreasing the duty cycle of the switching control circuitry, anddecrease the current of the power to be transferred by increasing theduty cycle of the switching control circuitry.
 20. The system of claim19, wherein the power extractor further includes: switching circuitry tocontrol the power transfer circuitry; and switching control circuitry tocontrol a duty cycle of the switching circuitry, wherein the powerchange analysis circuitry operates in different modes and wherein in anordinary operating mode, under some conditions, the power analysiscircuitry causes the power transfer circuitry to decrease the current ofthe power to be transferred by decreasing the duty of the switchingcontrol circuitry, and increase the current of the power to betransferred by increasing the duty cycle of the switching controlcircuitry.
 21. The system of claim 20, wherein the power transfercircuitry includes a first energy transfer circuit connected to thepower source to continuously transfer energy, a second energy transfercircuit connected to the load to continuously transfer energy, and anintermediate energy transfer circuit connected between the first andsecond energy transfer circuits to discontinuously transfer energybetween the first and second energy transfer circuits.
 22. The system ofclaim 21, wherein the switching circuitry is to modulate voltages at afirst node between the first and intermediate energy transfer circuits,and at a second node between the intermediate and second energy transfercircuits.
 23. The system of claim 21, wherein a frequency of operationof the switching circuitry is dynamically adjusted to maximizeefficiency of power transfer between the power source and the load. 24.The system of claim 19, wherein the power transfer circuitry includes afirst energy transfer circuit connected to the power source tocontinuously transfer energy, a second energy transfer circuit connectedto the load to continuously transfer energy, and an intermediate energytransfer circuit connected between the first and second energy transfercircuits to discontinuously transfer energy between the first and secondenergy transfer circuits.
 25. The system of claim 19, the power changeanalysis circuitry to further filter rapid power changes and voltagechanges at the first node.